Kikuchi Disease in Children: Case Report and Review of the Literature

Unilateral gluteal myositis as a unique presentation in mesenteric Kikuchi-Fujimoto disease

Kikuchi-Fujimoto disease (KFD) is a self-limiting disease, characterised by fever and cervical lymphadenopathy. Lymphadenopathy without cervical lymph node involvement is rare and may mimic lymphoma. Although KFD can be associated with extranodal involvement, muscle involvement has not been reported. Herein, we report a novel case of unilateral gluteal myositis associated with mesenteric KFD in a patient who presented with persistent fever and right hip pain. Radiological imaging revealed an inflammatory lesion on the right gluteal muscle and multiple enlarged abdominal lymph nodes. No cervical lymphadenopathy was observed. A mesenteric lymph node biopsy was performed, and the histopathological findings led to a diagnosis of KFD. By day 29, the patient's body temperature gradually returned to normal without any therapeutic intervention. Follow-up radiological imaging showed resolution of the gluteal lesion and a significant decrease in abdominal lymph node size. Considering the clinical course, the unilateral myositis may have developed as an extranodal involvement of KFD. Even if the clinical findings appear unrelated to those of KFD, a differential diagnosis that includes KFD should be considered in patients with unknown origin of fever.

Clinical features and recurrence predictors of histiocytic necrotizing lymphadenitis in Chinese children

OBJECTIVES

To characterize the clinical features and to identify the predictors of recurrence of histiocytic necrotizing lymphadenitis (HNL) in Chinese children.

STUDY DESIGN

This study retrospectively analyzed the clinical characteristics, laboratory and pathological findings, and recurrence status of children diagnosed with HNL at a single center in China from January 2018 to May 2023. Logistic regression analysis was employed to identify predictors of HNL recurrence.

RESULTS

181 Chinese children with histopathologically confirmed HNL were enrolled (121 males and 60 females). The mean age was 9.3 ± 2.9 years. The most prominent clinical features were fever (98.9%) and cervical lymphadenopathy (98.3%). Aseptic meningitis was the most frequent complication (38.5%), while hemophagocytic lymphohistiocytosis and autoimmune disease were rare (1.7% and 1.2%, respectively). Recurrence occurred in 12.7% of patients. Erythrocyte sedimentation rate (> 30 mm/h) was the significant predictors of HNL recurrence, with odds ratios of 6.107, respectively.

CONCLUSION

Our study demonstrates that fever and cervical lymphadenopathy are the most frequent clinical manifestations of HNL in Chinese children, which often coexist with aseptic meningitis. HNL patients with risk factors require follow-up for recurrence.

Clinical features of histiocytic necrotizing lymphadenitis in children

Due to its nonspecific clinical characteristics, histiocytic necrotizing lymphadenitis (HNL) is often misdiagnosed as a suppurative cervical lymphadenitis and lymphoma. Thus, this study aimed to investigate the clinical characteristics of HNL in pediatric patients. We retrospectively identified 61 patients with histopathologically confirmed HNL. Clinical and laboratory data, including age, sex, clinical manifestations, laboratory investigations, histological discoveries, treatment, and outcomes, were collected from the medical records to determine associations with extracervical lymph node (LN) involvement. The mean age of patients was 9.7 ± 2.8 years (range, 1.5-14.0 years), and the male-to-female ratio was 2.2:1. The most common systemic symptom was fever in all patients. The median pre-admission and total durations of fever were 13.0 (interquartile range [IQR]: 9.0-22.5 days) and 22.0 days (IQR: 17.0-33.0 days), respectively. Patients with temporary fever (< 2 weeks) had a higher peak temperature and were more likely to undergo LN biopsy after admission than those with a prolonged fever (≥ 2 weeks). Multivariate analysis revealed that peak temperature ≥ 40 °C was significantly associated with a longer fever duration (P = 0.023). Laboratory values showed leukopenia (68.9%), which presented more frequently in solitary cervical LNs than in extracervical LNs (82.4% vs. 52.9%, p = 0.027) in patients with prolonged fever.

CONCLUSIONS

HNL is often misdiagnosed in older children with persistent fever and lymphadenopathy, leading to unnecessary diagnostic tests and evaluations, inappropriate antibiotic administration, and mismanagement. A multidisciplinary team, including primary care providers, rheumatologists, and pathologists, can improve patient outcomes by increasing their awareness of this rare condition.

WHAT IS KNOWN

• Histiocytic necrotizing lymphadenitis (HNL) is characterized by fever, leukopenia, and neck lymphadenopathy with unknown etiology. • The lack of neutrophils or eosinophils in the histology, immunohistochemistry results help distinguish HNL from infectious causes. Although HNL is a self-limiting disease, antibiotics and steroid treatments were used inappropriately.

WHAT IS NEW

• A fever peak ≥ 40 °C was associated with a longer fever duration in HNL patients. Leukopenia presented more frequently in solitary cervical lymph node (LNs) than in extracervical LNs inpatients with prolonged fever. • Steroids are not recommended as a routine treatment, however, in some severe or relapsing cases with persistent symptoms, prednisolone (5 mg twice a day for 2 days) or other steroids (an equivalent dose of prednisolone) responded favorably.

Characterization of Kikuchi-Fujimoto Disease in Children and Risk Factors Associated with Its Course

OBJECTIVE

To outline the characteristics of Kikuchi-Fujimoto disease (KFD) in children and analyze factors associated with severe and recurring courses.

METHODS

Electronic medical records of children histopathologically diagnosed with KFD at Seoul National University Bundang Hospital from March 2015 to April 2021 were retrospectively reviewed.

RESULTS

A total of 114 cases (62 males) were identified. The mean patient age was 12.0 ± 3.5 years. Most patients came to medical attention with cervical lymph node enlargement (97.4%) and fever (85%); 62% had a high-grade fever (≥39°C). Prolonged fever (≥14 days) was seen in 44.3% and was associated with a high-grade fever (P = .004). Splenomegaly, oral ulcer, or rash was present in 10.5%, 9.6%, and 15.8%, respectively. Laboratory findings showed leukopenia, anemia, and thrombocytopenia in 74.1%, 49%, and 24%, respectively. Sixty percent of cases had a self-limited course. Antibiotics were initially prescribed in 20%. A corticosteroid was prescribed in 40% of patients and was associated with oral ulcer (P = .045) and anemia (P = .025). Twelve patients (10.5%) had a recurrence with a median interval of 19 months. No risk factor for recurrence was identified in multivariable analysis. Clinical characteristics of KFD were similar between our current and previous studies. However, antibiotics use decreased (P < .001); nonsteroidal anti-inflammatory drugs use increased (P < .001), and, although statistically not significant, corticosteroid treatment also increased.

CONCLUSIONS

Over a span of 18 years, the clinical characteristics of KFD did not change. Patients presenting with high-grade fever, oral ulcer, or anemia may benefit from corticosteroid intervention. All patients should be monitored for recurrence.